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Visit : Civildatas.blogspot.in, , MAHALAKSMI, ENGINEERING COLLEGE, TIRUCHIRAPALLI - 621213., QUESTION WITH ANSWERS, , sp, ot., in, , DEPARTMENT: CIVIL -IV, SEMESTE, , R:VII SUB.CODE/ NAME: CE 2033 / Ground Improvement Techniques, , UNIT V GROUT TECHNIQUES, PART - A (2 marks), , log, , 1. Define grouting., Grouting is defined as the process of injecting suitable fluid under pressure into the, subsurface soil or rock to fill voids, cracks and fissures for the purpose of improving the, soil., The fluid may be colloidal solutions, cement suspensions, chemical solutions etc., , s.b, , 2. Write the applications of grouting. (AUC MAY/JUNE 2013), , vil, d, , ata, , 1. Producing mass concrete structures and piles, 2. Fixing ground anchors for sheet pile walls, concrete pile walls, retaining walls, tunnels etc, 3. Repairing a ground underneath a formation or cracks, 4. Defects on building masonry or pavement, 5. Fixing the tendons in prestressed post tensioned concrete, 6. Filling the void between the lining and rock face in tunnel works, 7. Seepage control in soil, 8. Soil stabilization and solidification, 9. Vibration control, , Ci, , 3. Write the various types of grouting., , Suspension grouts, Solution Grouts, Colloidal solution grouts, , 4. What are the different types of grouts?, , Compaction grouting, Permeation grouting, Hydraulic fracturing, Jet grouting, , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , 5. Name the different methods of grout injection., , Bottom up, Top down, Circuit grouting, Tube-a-manchette, Point grouting, Electro-kinetic injection, , sp, ot., in, , 6. What are the two methods of mechanical stabilization?, Removal &Replacement, Dynamic compaction, Precompression, Insitu Replacement, Blast Densification, 7. How is stabilization of soil achieved by cement?, , log, , cement stabilisation - which uses higher percentages of cement and produces a stiff, semirigid pavement material.The design of cement-soil-water mixtures is based on selecting the, minimum cement content required to provide sufficient strength and durability to enable the, material to function as a satisfactory layer in the pavement structure. The amount of cement, required is determined by laboratory testing, usually using the unconfined compressive, strength test., 8. What are the methods adopted in construction of stabilized roads?, , ata, , s.b, , Stabilization with lime, Combined stabilization with lime and flyash, Stabilization with cement, Stabilization with RRP-235, Cost and strength of stabilized layers, Change of the strength in an unconfined compression in connection with the, comprehensiveness of the soil in lime and cement 7% and 5 kg RRP/100 m2, , vil, d, , 10. What are the various stages of action in lime stabilization?, gglomeration of fine clay particles, though base exchange;, weak cementing action, due to calcium carbonate formation; and, slow, long-term cementing action., , Ci, , 10. Write the various classes of chemicals used in stabilization of soil., pulverization;, cement content;, moisture content;, mixing;, compaction;, finishing;, curing, ., , 11. Define Suspension grouts and group grouts . (AUC NOV /DEC 2010), , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , Suspension grouts, These are multi-phase systems capable of forming sub systems after being subjected to natural, sieving processes, with chemical properties which must ensure that they do not militate against, controlled properties of setting and strength., Water in association with cement, lime, soil, etc., constitute suspensions., Emulsion (asphalt or bitumen) with water is a two-phase system which is also included under, suspension., , Solution Grouts, , sp, ot., in, , These are intimate one-phase system retaining an originally designed chemical balance until, completion of the relevant reactions. Silicate, derivatives, lignosulphite derivatives, phenoplast resins etc. come under this category., , s.b, , log, , 12. State the conditions required the injection grouting method ?, (AUC NOV /DEC 2010), The grouting process the basic information to be obtained is the, weight for suspension grouts and volume for solution grouts flow rate, along with pressures for both., The measurements of weight or volume should be made accurately so, as confirm mix proportions., In solution grouting positive displacement meters may be used for, these purpose, 13. Discuss the basic function of grouting . (AUC MAY/JUNE 2013), Grouting is defined as the process of injecting suitable fluid under pressure into the subsurface, soil or rock to fill voids, cracks and fissures for the purpose of improving the soil., The fluid may be colloidal solutions, cement suspensions, chemical solutions etc., 14. Write few words about jet grouting (AUC NOV /DEC 2012), The jet grouting technique is developed in the 1960s. However, because of its unique, properties, it is becoming quite popular in the civil engineering works. Its main applications, are: • Grouting of clay / silt soils which is not suitable for TAM grouting technique., , Ci, , vil, d, , ata, , • Jet grout wall and roof are used to reinforce tunnel portal excavation works., , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , Part –B, 1. Describe in detail about the various methods of grouting with neat sketches. (AUC MAY/JUNE 2013), , Suspension grouts, , sp, ot., in, , These are multi-phase systems capable of forming sub systems after being subjected to natural, sieving processes, with chemical properties which must ensure that they do not militate against, controlled properties of setting and strength., Water in association with cement, lime, soil, etc., constitute suspensions., Emulsion (asphalt or bitumen) with water is a two-phase system which is also included under, suspension., , Solution Grouts, , These are intimate one-phase system retaining an originally designed chemical balance until, completion of the relevant reactions. Silicate, derivatives, lignosulphite derivatives, phenoplast resins etc. come under this category., , o, , Compaction grouting, Permeation grouting, Hydraulic fracturing, Jet grouting, , s.b, , i., ii., iii., iv., , log, , Colloidal solution grouts, Solutions in which the solute is present in the colloidal state are known as colloidal solutions., Chemical grouts fall into this category., , Compaction grouting, , Ci, , vil, d, , ata, , The basic concept is of injecting an highly viscous grout with high internal friction, injected into a, compactable soil, the grout acts as a radial-hydraulic jack and physically displaces the soil particles thus, achieving controlled densification., Minimum disturbance to, • Grouting adjacent to, the structure and, unsupported slopes may be, surrounding ground,, ineffective., • Minimum risk during, • Not suitable in, construction., decomposable materials., • Ground water not affected., • Danger of filling, • Supports all portions of, underground pipes with structures., grout., • Effectiveness questionable in saturated clays, , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , Permeation grouting, , sp, ot., in, , Grout is injected into the soil at low pressure and fills the voids without significantly changing the, soil’s structure and volume., Variety of binders are used with this technique, the choice of which is dictated mainly by the, permeability of the soil., Merits:, Solidifies the soil, Cost of grout increases as, Adds to its cohesion permeability decreases, Reduces permeability, Cannot be adopted when permeability decreases below 10-6cm/s, Demerits:, , log, , Hydrofracturing uses high-mobility grout to split the ground and thereby create lifting or densification, under structures or other facilities., This process is often undertaken as a reaction to movements while tunnel excavation is in progress., The main disadvantage of this method is that it is difficult to control., , ata, , s.b, , 2. Write short notes on, (a) Pre-grout investigation, i. To determine method and extent of grouting, ii. Requires geological and drilling investigation with pumping tests, iii. Geological investigation reveals geological features and flaws like fissures, faults, zones of, weakness, dip, strike etc., iv. Detailed, v. exploration and sampling are done to, vi. determine soil properties like strength, permeability etc., vii. Pumping tests are done for estimating pumping pressure, grout type and pattern., , vil, d, , (b) Grout holes pattern, a. Grout hole pattern is usually selected in such a way that a curtain of grouted soil is, formed, b. This is done by drilling holes in a row followed by secondary and tertiary holes to plug, the gaps in the initial rows of grout holes, c. Grout holes are drilled usually in vertical direction but inclined holes are also drilled to, intersect maximum number of bedding planes or joints, , Ci, , (c) Selection of grout characteristics, o A grout must be able to penetrate the voids of the mass to be injected, o A grout should be resistant to chemical attack, o The grout should be capable of developing sufficient shear strength to resist the hydraulic gradient, imposed during injection or due to ground water flow, , 3. Enumerate with a neat sketch the grouting plant and equipment necessary and the, procedure for carrying out grouting operations., , Grouting Plant and Equipment, a. A grouting plant includes a mixer, an agitator, a pump, and piping connected to grout, holes., Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , b., , s.b, , log, , sp, ot., in, , c., d., e., f., g., h., , Two systems: single line type and circulating type. In the circulation type, the unused, grout is returned to the agitator and in the single-line type the grout refused is wasted., The basic items required for a grouting plant and their functions are:, Measuring tank-to control the volume of grout injected., Mixer-to mix the grout ingredients, Agitator-to keep the solid particles in suspension until they are pumped, Pump-to draw the grout from the agitator to deliver to the pumping line., Control fittings-to control the injection rate and pressure., , Ci, , vil, d, , ata, , 4. Write a detailed note on the various grout injection methods., Injection methods, Bottom up, Grouting is done from bottom of the hole upwards, Top down, Grouting is done from top of the hole downwards, Circuit grouting, Similar to bottom up but the excess grout pumped down comes out via the drill hole, which, eliminates clogging, Tube-a-manchette, Grouting is done through a tube called tube-a-manchette with rubber sleeves through which grout, spreads to surrounding soil, Point grouting, Injection is done through the tip or point of a driven or jetted lance, Pressure injected lime, Injection of lime slurry under high pressure of 350 to1400 kN/m2 usually for shallow stabilization, depths of upto 3m, , Electro-kinetic injection, Chemical stabilizers are introduced at anode and are carried towards cathode via electroosmosis mainly under conditions that require confinement or to avoid disturbance, , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , 5. What is grout injection measurement? Why is grout monitoring necessary? (AUC NOV /DEC 2010), , s.b, , log, , sp, ot., in, , The grouting process the basic information to be obtained is the weight for, suspension grouts and volume for solution grouts flow rate along with, pressures for both., The measurements of weight or volume should be made accurately so as, confirm mix proportions., In solution grouting positive displacement meters may be used for these, purpose, The floe rate of the grouting during injection should be continuously by, monitored and plotted against the grout pressure to ascertain the condition, below the ground. Different types of flow meters are available in the market., Pressures should be also be monitored at the grout stations , if possible ,, continuously ., Bourdon tube gauges are also used to measure pressure periodically which, usually take a dreadful battering on most grouting jobs and yet provide such, valuable information that they are worth taking care of, Grouting monitoring is not just measurement of flow rate , pressure , etc , but, it is making aa positive assessment of he results of the injected grout ., This can be accomplished by the conventional methods by obtaining, undisturbed soil, rock samples of the grouted material and then testing them, for the strength , permeability , compressibility adopting standard lab methods, The constraint about this approach is the selection of test boring location ,, depth of sampling and finance . a better approach is to be use indirect, methods such as geophysical or non- destructive testing methods which, provide a continuous trace of continuous before and after grouting either, along either along the grounds surface or within adjacent grout pipes ., Grout monitoring procedures at the various times during the grouting process, :, , ata, , Grouting activity:, , vil, d, , Prior grouting, During drilling, Grout materials, During grout, After grouting, , Minor monitoring effect only :, , Ci, , Inspect equipment set elevation survey points and establish monitoring, plan and procedures, Certificates of compliance trial grout mixes, Monitor injection pressure and flow rate grout samples for get time and, storage, Plot grout –take log, Heave measurements on survey paints, Final heave survey final review an signoff, Intense monitoring effort:, Inspect equipment set elevation survey points and establish monitoring, Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , plan and procedures, Conduct pre grout radar and cross hole acoustic surveys, Certificates of compliance trial grout mixes , independent lab tests, Monitor and record injection pressure and flow rate (strip chart ), Grout emplaces for gel time and storage, , sp, ot., in, , Plot grout take log, \heave measurements on survey points, In situ deformation measurements as appropriate, Pore –pressure data, In-situ resistivity, Acoustic emission monitoring for hyrofracturing, Final heave survey, Post grout radar and acoustic surveys, Final review and signoff, , log, , 6. Describe in detail the various applications of grouting?, (AUC NOV /DEC 2012), , vil, d, , ata, , s.b, , 1. Producing mass concrete structures and piles, 2. Fixing ground anchors for sheet pile walls, concrete pile walls, retaining walls tunnels etc, 3. Repairing a ground underneath a formation or cracks, 4. Defects on building masonry or pavement, 5. Fixing the tendons in prestressed post tensioned concrete, 6. Filling the void between the lining and rock face in tunnel works, 7. Seepage control in soil, 8. Soil stabilization and solidification, 9. Vibration control, 10. Rock fissure grouting technique has a long history of application in civil engineering., 11. Its main applications are:, •, , Sealing rock mass underneath and at ends of dams to prevent seepage or, leaking of the reservoirs., , •, , Sealing rock mass above and underneath a rock tunnel to prevent water, seepage into the excavated tunnel., , Ci, , Cementing fractured rock mass., Although Rock Fissure Grouting technique can be used to, cemented sugar clubs rock formation, like in slope stability projects, its main application is in the, field of water stopping, especially in tunnel excavation project., , Application of TAM, •, , Main applications of the TAM grouting technique are: o Sealing soil mass above and underneath a tunnel excavated in soil under compressed air condition., o Sealing soil mass behind the soldier pile wall, pipe pile wall etc., o Sealing “windows” in cofferdams, o Consolidation of loose soil mass (cohesion less granular sand), Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , o Sealing underlying soil of dams, Application, The jet grouting technique is developed in the 1960s. However, because of its unique properties, it is, becoming quite popular in the civil engineering works. Its main applications are: -, , •, , Grouting of clay / silt soils which is not suitable for TAM grouting technique., , •, , Jet grout wall and roof are used to reinforce tunnel portal excavation works., , •, , Sealing of windows of coffer dams, , Used as jet grout raft to reinforce cofferdam to limit its deflection and thus decrease the settlement, caused by the excavation works, , Application, •, •, , Compaction grouting is a soil and foundation support improvement system that increases the bearing, capacity of soils., A major advantage of using compaction grouting is that its maximum peak effect is realized in the, weakest or softest strata of the infrastructure support., Its main applications are as follows:, , log, , •, , sp, ot., in, , •, , •, , a. Lateral static densification of soils., , b. Lifting and re-leveling roads, bridges, and other existing structures, , s.b, , c. Blocking of flow-path of viscous liquids through stratum layers and rock cracks, voids, and, fractures, d. Construction of underpinning, , d. The remediation of sinkholes, , ata, , Application., , vil, d, , Percussion drilling produces acceptable grout holes, and, generally, is the most economical method of drilling shallow holes. This advantage, decreases with depth and disappears at depths from 75 to 125 ft depending on the type of, rock. In operation, the edges or wings of the bit wear away so that a progressively smaller hole, is drilled. Therefore, when pertinent, the specifications should state the minimum acceptable, size of grout hole., , Ci, , 7. Enumerate in detail the different methods of mechanical stabilization., Mechanical stabilization., , Mechanical stabilization is accomplished by mixing or blending soils of two or, more gradations to obtain a material meeting the required specification. The soil, blending may take place at the construction site, a central plant, or a borrow, area. The blended material is then spread and compacted to required densities, by conventional means, , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , Methods of Mechanical stabilization, , sp, ot., in, , Removal &Replacement:Excavate unsuitable soil and replace compaction fill used when soil is too loose use same, soil for fill which has high unit weight which have engineering properties., Removal will be done first soil has excessive organics. It is expensive method, because we want to dispose and import the soil. Both is suitable only above ground water table., Earthwork operation is different if soil is wet., Precompression:-, , For improving soil we have to cover them with a temporary surcharge fill. Preloading, surcharging., Suitable for soft clayey and silty soils because static weight of fill cause them consolidate t, hus improves settlement of strength properties after the properties, attains, surcharge id removed and construction proceeds surcharge fills 3-8 m, settlement 0.3-1 m., , log, , Insitu densification:Method of densifing shallow soil using heavy vibratory rollers upto 2m., Vibrocompaction: Two methods Terraprobe and vibroflot. Terraprobe consists consists, vibratory pile hammer attached to steel pipe. Pile is vibrated., A vibroflot contains vibrator and water jet. Depth upto 3- 15m, silt content less than <12-15%., Dynamic compaction:, , s.b, , cost effective method of densifing loosen sandy and silty soil. Primary zone of influence, typically extends to depth of 5-10m with lesser improvements below these depths., It is used to treat 5-10m with lesser improvements below these depths ., It is used to treat liquefaction prone soil, collapsible soil., It is evaluated by performing STP&CPT tests before and after construction., , ata, , Blast Densification: curious than above one. It consist of drilling a series of boring & using them to place, explosive underground. It is effective in clean sands., Because of vibration of safety issues it is only suitable for remote sites., , vil, d, , Insitu Replacement:It is intended to provide load bearing members that extend through weak strata., The stone column acts as vertical drain thus helps in accelerate consolidation settlement of, mitigate seismic liquefaction problem., , Ci, , Modern equipments used for stabilization, , Visit : Civildatas.blogspot.in

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8. Write a detailed note on(AUC NOV /DEC 2010), (a) Portland cement stabilization, Portland Cement Stabilisation, Cement treatment takes two forms:, , sp, ot., in, , Visit : Civildatas.blogspot.in, , log, , cement modification - which uses up to about 3 percent cement (by mass) and aims to reduce plasticity, without producing a rigid material; and, , cement stabilisation - which uses higher percentages of cement and produces a stiff, semi-rigid, pavement material., , s.b, , The design of cement-soil-water mixtures is based on selecting the minimum cement content required to, provide sufficient strength and durability to enable the material to function as a satisfactory layer in the, pavement structure. The amount of cement required is determined by laboratory testing, usually using the, unconfined compressive strength test., , ata, , Construction practices significantly effect the subsequent performance of cement stabilised materials, and, each of the following aspects must be closely controlled:, 1. pulverization;, , vil, d, , 2. cement content;, , 3. moisture content;, 4. mixing;, , 5. compaction;, , Ci, , 6. finishing;, , 7. curing, ., Rapid compaction after mixing is possibly, most important as cement hydrates, relatively quickly, , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , (b) Bituminous stabilization, The addition of a bituminous material to soil or crushed rock material is intended, to either provide a cohesive binder for non-plastic materials, or to waterproof a cohesive material., The type of binder best suited to a particular application depends on cost, soil type, climate, and, availability of mixing equipment. The most appropriate binder from a technical perspective is determined, , cut-back bitumen, bitumen emulsion and tars., , Insitu deep mixing:-, , sp, ot., in, , by laboratory testing. Bituminous binders which have been used for stabilisation work include bitumen,, , Uses rotating mixer shafts, paddles or jet that penetrates into ground while injecting of mixing, Portland cement. It includes deep cement mixing, deep jet mixing. The treated soil has greater, , log, , strength, reduced compressibility than original soil., , Surface mixing: upper soil gets ripped, applying the admixture mixing with special, equipment and compacting. Once mixture has cured it forms very hard and durable soil., , s.b, , It forms a layer called sub base in highways and airports. It is no more than 200 mm., Reinforcement:-tensile reinforcement members improve the soil stability of load carrying capacity., , ata, , Used in construction of compacted fill slopes of earth retaining structures., , vil, d, , 8. Describe in detail how chemicals are used in stabilizing the soil with the help of an, example. (AUC MAY/JUNE 2013) (AUC NOV /DEC 2012), Chemical stabilization., Chemical stabilization is achieved by the addition of proper percentages of, cement, lime, fly ash, bitumen, or combinations of these materials to the soil., , Ci, , The selection of type and determination of the percentage of chemical to be used is dependent, upon the soil classification and the degree of improvement in soil quality desired., Generally, smaller amounts of chemicals are required when it is simply desired to modify soil, properties such as gradation, workability, and plasticity. When it is desired to improve, the strength and durability significantly, larger quantities of additive are used., , Visit : Civildatas.blogspot.in

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Visit : Civildatas.blogspot.in, , After the additive/chemical has been mixed with the soil, spreading and, , sp, ot., in, , compaction are achieved by conventional means., , Hydrated Lime Stabilisation, , log, , When hydrated lime (or quick lime) is aded to a soil in the presence of moisture a series of, reactions is set in motion. The actual physical and chemical processes which occurs are, quite complex. The reaction between lime and soil can be considered in three major, overlapping stages:, , s.b, , agglomeration of fine clay particles, though base exchange;, weak cementing action, due to calcium carbonate formation; and, , ata, , slow, long-term cementing action., , The reaction of lime with soil depends on the type of clay minerals present in the soil., For the reaction to be effective the soil must contain kaolinite or montmorillonite minerals., , vil, d, , If the clay minerals are illite or chlorite, a pozzolan must be added to produce the desired effects., The normal pozzolan which is used is fly ash., Small amounts of lime (1% to 3%) may reduce the soil plasticity and this process is referred to, as lime modification. The more normal process is the addition of 3% to 6% lime, although, , Ci, , there is now a school of thought which suggests the process is more effective with fairly, high lime contents (in the order of 10%)., , Mix design is based on the selection of the lime content necessary to provide required strength, and durability. Lime contents may be determined by strength tests (e.g. CBR), or, by Atterberg Limits, or by pH values., Visit : Civildatas.blogspot.in